For example, in the case of an electromagnetic valve such as an electromagnetic fuel injection valve, inherent information about the model name, production lot number, serial number, or the like of the product and information including contents that are changeable even in the case of the same model are indicated on a flat portion that is provided at one axis-direction end portion of a cylindrical case and extends in a direction perpendicular to the axis, by use of a marking formed through laser irradiation or the like, and rust-proof plating processing is applied to the marking (e.g., refer to Patent Document 1). The recognition of the contents of the indication through the marking is implemented by peeling off the rust-proof plating and viewing the marking; because the flat portion, of the case, where the marking is provided is exposed outward, the work of recognizing the indication is facilitated.
In the case where, for the same purpose as that of the formation of a marking on the case of the electromagnetic valve, a marking is formed on the stator of an electric rotating machine, e.g., an in-vehicle AC generator, a flat surface that is an axis-direction end portion of the laminated iron core of the stator and extends in a direction perpendicular to the axis corresponds to the flat surface of one end portion of the cylindrical case of the foregoing electromagnetic valve; therefore, by utilizing, as a place where a marking is formed, the flat surface of the axis-direction end portion of the laminated iron core, a marking is readily formed, as the application of the technology for forming a marking on a flat portion of the case of an electromagnetic valve.    [Patent Document 1] Japanese Patent Laid-Open Pub. No. 2005-226808